The keys
()
method of the CacheStorage
interface returns a Promise
that will resolve with an array containing strings corresponding to all of the named Cache
objects tracked by the CacheStorage
object in the order they were created. Use this method to iterate over a list of all Cache
objects.
You can access CacheStorage
through the global caches
property.
Syntax
caches.keys().then(function(keyList) { //do something with your keyList });
Parameters
None.
Return value
a Promise
that resolves with an array of the Cache
names inside the CacheStorage
object.
Examples
In this code snippet we wait for an activate
event, and then run a waitUntil()
block that clears up any old, unused caches before a new service worker is activated. Here we have a whitelist containing the names of the caches we want to keep (cacheWhitelist
). We return the keys of the caches in the CacheStorage
object using keys()
, then check each key to see if it is in the whitelist. If not, we delete it using CacheStorage.delete()
.
then.addEventListener('activate', function(event) { var cacheWhitelist = ['v2']; event.waitUntil( caches.keys().then(function(keyList) { return Promise.all(keyList.map(function(key) { if (cacheWhitelist.indexOf(key) === -1) { return caches.delete(key); } }); }) ); });
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'CacheStorage: keys' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
keys | Chrome Full support 40 | Edge Full support 16 | Firefox
Full support
44
| IE No support No | Opera Full support 27 | Safari Full support 11.1 | WebView Android Full support 40 | Chrome Android Full support 40 | Firefox Android Full support 44 | Opera Android Full support 27 | Safari iOS Full support Yes | Samsung Internet Android Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- See implementation notes.
- See implementation notes.